Final answer:
The primary source for solving EO complaints in the military is the Equal Opportunity Advisor, tasked with handling and advising on EO matters.
Step-by-step explanation:
The primary source for solving Equal Opportunity (EO) complaints within the military structure is b. Equal Opportunity Advisor. When a soldier or service member has an EO complaint, they are usually advised to first bring the matter to the attention of their EO Advisor. This designated individual is trained to handle EO issues and is responsible for advising commanders on EO matters, including complaints, education, and training. The EO Advisor aims to resolve complaints at the lowest possible level. However, if the situation warrants, or if the complaint is not resolved satisfactorily, it may be escalated to other resources such as the chain of command, the Inspector General, or the military police.